Electronic mail, or e-mail, has become pervasive. For instance, e-mail has become mission-critical for many businesses in enabling employees to communicate. Generally, people are relying on e-mail more than ever. As a result, the consequences of a recipient not receiving an e-mail can be significant. There are a number of reasons why an e-mail may not be received and/or read by the designated recipient. For example, the e-mail may have been lost in transit due to a network or host failure. Or, an e-mail may be filtered out by a spam filter, which filters out so-called junk e-mail, at the sending side or at the receiving side. Moreover, different e-mail providers use different spam filters, and the filters are always evolving. Thus, an e-mail that may have been successfully received in the past may not be received in the future if re-sent. Further, an e-mail may not be read simply because the recipient did not check his or her e-mail inbox.
A solution is needed for providing receipts for e-mail messages in a flexible, user-friendly manner which is compatible across different e-mail systems, and which maintains the privacy of e-mail recipients.